Field of Invention and Description of Prior Art
The present invention relates to a system for determining the cause of chest pain by monitoring and recording changes in the acidity of a patient's esophageal tract over an extended period of time. A preferred embodiment of the present invention relates to a device for monitoring and recording gastroesophageal pH simultaneously with data related to other causes of chest pain such as esophageal spasms and irregular heart activity.
Gastroesophageal reflux, regurgitating stomach contents into the the esophagus (the passage extending from the pharynx to the stomach), may cause heartburn, chest pain, or difficulty in breathing or swallowing. Monitoring of gastroesophageal reflux has included testing the esophagus for acid sensitivity, measuring the gastroesophageal pressure difference, barium radio-esophagram and perfusion of acid into the stomach with subsequent pH monitoring. All of the above tests have encountered problems and currently monitoring of lower esophageal acidity level, or pH, is considered to be the most reliable technique.
Since gastroesophageal reflux normally occurs on an irregular or sporadic basis it is preferable to develop a history of activity over a prolonged period of time for diagnostic purposes. A monitoring system for recording gastroesophageal reflux incidents preferably records the cycle of regurgitation and clearance. Correlating incidents of gastroesophageal reflux with eating, sleeping and other daily activities provides helpful information to a physician in diagnosing the cause of the gastroesophageal reflux.
In infants, continuous monitoring of gastroesophageal reflux provides an objective method for evaluating the relationship between gastroesophageal reflux and apneic spells associated with Sudden Infant Death Syndrome.
Monitoring a patient at bedside is of only limited value since the patient's activities are severely curtailed which reduces the usefulness of the data collected. One example of such a system is disclosed in the publication entitled "An Integrated System for Esophageal pH Monitoring". Lee, R. J., et al., IEEE/Engineering in Medicine and Biology Society First Annual Conference, Session 2, Denver, Colo., (October 1979), pp. 53-54, which describes the use of a large bedside monitor for monitoring esophageal pH, heartrate and repiration of a patient from bedside.
Another system is a portable gastroesophageal reflux pH monitor which periodically records pH reading in a digital memory on discrete CMOS IC's. The discrete readings are later converted into analog data on a chart recorder. An example of one such system is described in the publication entitled "A Solid State Portable Gastroesophageal Reflux pH Recorder", Sanders, G., et al., 33 ACEMB, Washington, D.C., (September-October 1980), p. 54. The primary disadvantage of such a device is that the entire system is useable only for gastroesophageal reflux monitoring and would be a considerable investment for a hospital requiring few gastroesophageal reflux monitoring studies.
Another alternative by which twenty-four hour monitoring of gastroesophageal pH can be accomplished is disclosed in the publication entitled "Twenty-four Hour Esophageal pH Monitoring by Telemetry", by Falor, W. H., et al., The American Journal of Surgery, Vol. 142, (October 1981), pp. 514-516. In that system, a battery-powered pH meter and transmitter are worn in a shoulder harness which transmits pH readings to a receiver on a remotely located strip chart recorder. Such a system is effective in monitoring gastroesophageal reflux incidents for extended periods of time but is subject to loss of data caused by radio interference. In addition, the limitation on a patient's activity caused by the need to stay within the range of the receiver make the device inappropriate for persons who normally lead a very active life which would take them out of the range of the receiver.
All of the above disadvantages are overcome by the economical, accurate and efficient gastroesophageal reflux monitor of the present invention.
Another disadvantage of each of the above devices is that they are limited to monitoring GER. Frequently, patients suffering from chest pain may be suffering from spasms of the esophagus, cardiac pain or GER. Previously each of the conditions was separately tested for with separate test equipment. Generally the tests are sequentially performed until the cause for the chest pain was determined. Separately administering the tests is time consuming and therefore delays treatment.
The prior art devices fail to provide a portable combined gastroesophageal reflux monitor, esophageal manometer and EKG monitor which overcomes the disadvantages arising from the need to separately administer the three different tests. Such a device is described herein with reference to the preferred multi-monitor of the present invention.